Influence of injection valve opening manner and injection timing on mixing effect of direct injection compressed natural gas–fueled engine

2020 ◽  
pp. 146808742093135
Author(s):  
Tianbo Wang ◽  
Lanchun Zhang ◽  
Shaoyi Bei ◽  
Zhongwei Zhu
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Injection Timing ◽  
Mixing Process ◽  
Mixing Effect ◽  
Injection Mode ◽  
Valve Opening ◽  
Gas Fuel ◽  
Gas Fueled

In order to improve the control precision of in-cylinder mixing and combustion process, and to avoid the engine power drop because of the port fuel injection mode, it becomes a tendency to inject gas fuel into cylinder directly, with the help of the high-pressure gas-fueled injection device. However, considering that the mixing speed of gas fuel with air is usually slower than that of gasoline or diesel, the gas fuel direct injection mode tends to cause poor mixing performance and insufficient combustion in engine. Based on this situation, in-cylinder mixing process of direct injection gas–fueled engine is taken as the research object in this article. The three-dimensional transient computational fluid dynamics model of the injection and mixing process in gas-fueled direct injection engine is established to analyze the effects of the poppet valve opening manner and injection timing on the in-cylinder mixing homogeneity. The results indicate that delaying the injection timing can improve the wall impact strength and help to form a tumble flow in the cylinder. The stronger wall impact and tumble flow can reverse the natural diffusion law and greatly improve the in-cylinder mixing effect. Under the same injection timing conditions, although the pull-open valve has a larger injection penetration distance, the in-cylinder mixing effect is still worse than the push-open one. This is because, for the push-open valve, the fuel jet will be around the slope of the valve, which is beneficial to improve the mixing effect.

scholarly journals Investigation into the effect of different fuels on ignition delay of M-type diesel combustion process

2008 ◽  
Vol 12 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Dzevad Bibic ◽  
Ivan Filipovic ◽  
Ales Hribernik ◽  
Boran Pikula
Keyword(s):  
Diesel Engine ◽  
Ignition Delay ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Injection System ◽  
Biodiesel Fuel ◽  
Injection Timing ◽  
Injection Angle ◽  
Start Of Injection

An ignition delay is a very complex process which depends on a great number of parameters. In practice, definition of the ignition delay is based on the use of correlation expressions. However, the correlation expressions have very often limited application field. This paper presents a new correlation which has been developed during the research project on the direct injection M-type diesel engine using both the diesel and biodiesel fuel, as well as different values of a static injection timing. A dynamic start of injection, as well as the ignition delay, is defined in two ways. The first approach is based on measurement of a needle lift, while the second is based on measurement of a fuel pressure before the injector. The latter approach requires calculation of pressure signals delay through the fuel injection system and the variation of a static advance injection angle changing. The start of a combustion and the end of the ignition delay is defined on the basis of measurements of an in-cylinder pressure and its point of separation from a skip-fire pressure trace. The developed correlation gives better prediction of the ignition delay definition for the M-type direct injection diesel engine in the case of diesel and biodiesel fuel use when compared with the classic expression by the other authors available in the literature.

Effect of Injection Timing on Combustion Characteristics of a DI Diesel Engine Fuelled with Pistacia chinensis Bunge Seed Biodiesel

2012 ◽  
Vol 614-615 ◽  
pp. 337-342
Author(s):  
Li Luo ◽  
Bin Xu ◽  
Zhi Hao Ma ◽  
Jian Wu ◽  
Ming Li
Keyword(s):  
Combustion Temperature ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Characteristics ◽  
Injection Timing ◽  
Brake Specific Fuel Consumption ◽  
Cylinder Pressure ◽  
Combustion Duration ◽  
Di Diesel Engine ◽  
Maximum Combustion Temperature

In this study, the effect of injection timing on combustion characteristics of a direct injection, electronically controlled, high pressure, common rail, turbocharged and intercooled engine fuelled with different pistacia chinensis bunge seed biodiesel/diesel blends has been experimentally investigated. The results indicated that brake specific fuel consumption reduces with the increasing of fuel injection advance angle and enhances with the increasing of biodiesel content in the blends. The peak of cylinder pressure and maximum combustion temperature increase evidently with the increment of fuel injection advance angle. However, the combustion of biodiesel blends starts earlier than diesel at the same fuel injection advance angle. At both conditions, the combustion duration and the peak of heat release rate are insensitive to the changing of injection timing.

CFD Modelling of the Effects of Injection Timing on the Combustion Process and Emissions in an HSDI Diesel Engine

2012 ◽  
Author(s):  
Raouf Mobasheri ◽  
Zhijun Peng
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Cfd Simulation ◽  
Direct Injection ◽  
Combustion Process ◽  
Injection Timing ◽  
Cfd Modelling ◽  
Combustion Modeling ◽  
Pressure Trace ◽  
Hsdi Diesel Engine

High-Speed Direct Injection (HSDI) diesel engines are increasingly used in automotive applications due to superior fuel economy. An advanced CFD simulation has been carried out to analyze the effect of injection timing on combustion process and emission characteristics in a four valves 2.0L Ford diesel engine. The calculation was performed from intake valve closing (IVC) to exhaust valve opening (EVO) at constant speed of 1600 rpm. Since the work was concentrated on the spray injection, mixture formation and combustion process, only a 60° sector mesh was employed for the calculations. For combustion modeling, an improved version of the Coherent Flame Model (ECFM-3Z) has been applied accompanied with advanced models for emission modeling. The results of simulation were compared against experimental data. Good agreement of calculated and measured in-cylinder pressure trace and pollutant formation trends were observed for all investigated operating points. In addition, the results showed that the current CFD model can be applied as a beneficial tool for analyzing the parameters of the diesel combustion under HSDI operating condition.

Diesel engine performance mapping using a parametrized mixing time model

2017 ◽  
Vol 19 (2) ◽  
pp. 202-213 ◽  
Author(s):  
Michal Pasternak ◽  
Fabian Mauss ◽  
Christian Klauer ◽  
Andrea Matrisciano
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Mixing Time ◽  
Combustion Process ◽  
Engine Performance ◽  
Injection Timing ◽  
Engine Control ◽  
Reactor Model ◽  
Time Model ◽  
Tabulated Chemistry

A numerical platform is presented for diesel engine performance mapping. The platform employs a zero-dimensional stochastic reactor model for the simulation of engine in-cylinder processes. n-Heptane is used as diesel surrogate for the modeling of fuel oxidation and emission formation. The overall simulation process is carried out in an automated manner using a genetic algorithm. The probability density function formulation of the stochastic reactor model enables an insight into the locality of turbulence–chemistry interactions that characterize the combustion process in diesel engines. The interactions are accounted for by the modeling of representative mixing time. The mixing time is parametrized with known engine operating parameters such as load, speed and fuel injection strategy. The detailed chemistry consideration and mixing time parametrization enable the extrapolation of engine performance parameters beyond the operating points used for model training. The results show that the model responds correctly to the changes of engine control parameters such as fuel injection timing and exhaust gas recirculation rate. It is demonstrated that the method developed can be applied to the prediction of engine load–speed maps for exhaust NOx, indicated mean effective pressure and fuel consumption. The maps can be derived from the limited experimental data available for model calibration. Significant speedup of the simulations process can be achieved using tabulated chemistry. Overall, the method presented can be considered as a bridge between the experimental works and the development of mean value engine models for engine control applications.

Experimental investigation of particle number reduction in turbocharged GDI engines

Trudy NAMI ◽  
2022 ◽  
pp. 31-40
Author(s):  
A. V. Gontyurev ◽  
N. S. Zuev
Keyword(s):  
Particulate Matter ◽  
Fuel Injection ◽  
Combustion Process ◽  
Gasoline Direct Injection ◽  
Practical Significance ◽  
Injection Timing ◽  
Catalytic Converters ◽  
Environmental Standards ◽  
The Future ◽  
Particulate Matter Formation

Introduction (problem statement and relevance). Now it is difficult to imagine the automotive industry without constant improvement of the power plant. This is due to the constant tightening of environmental standards, so in environmental standards Euro 6 there is a limit of the countable concentration of particulate matters. To meet the Euro 6 environmental standard, vehicle manufacturers use catalytic converters, and gasoline particle filters (GPF). These methods of reducing the emissions of the exhaust gas are quite common, but they also have a limitation on the service life. The use of only catalytic converters and GPF may not be sufficient to meet the Euro 7 standards in the future. So, there is a need to reduce emissions with exhaust gases by improving the combustion process.The purpose of work is to investigate the combustion process of a turbocharged gasoline direct injection engine to reduce particulate matter by increasing the injection pressure and optimizing the injection timing. Methodology and research methods. The studies are of an experimental nature, the reliability of the data is confirmed by the use of modern measuring equipment and post processing of the measured data. Scientific novelty and results. The fuel injection parameters, which have a significant influence on the particulate matter formation and oxidation are defined.Practical significance. The recommendations to reduce particulate matter formation and to meet the requirements of the future Euro standards are given.

Investigation of Performance and Fuel Economy for Cylinder Deactivation Engine at Part Load Operation

2016 ◽  
Vol 819 ◽  
pp. 443-448 ◽  
Author(s):  
S.F. Zainal Abidin ◽  
Mohd Farid Muhamad Said ◽  
Azhar Abdul Aziz ◽  
Mohd Azman Abas ◽  
N.I. Arishad
Keyword(s):  
Fuel Economy ◽  
Fuel Injection ◽  
Injection Timing ◽  
Original Performance ◽  
Part Load ◽  
Automotive Engine ◽  
Engine Efficiency ◽  
Efficiency Performance ◽  
Valve Opening ◽  
Load Conditions

In automotive engine applications, the spark ignition (SI) engines can operate at various engine speed and load conditions. However, most of the time was spend at part load operations, where they operate below their rated output especially during cruising or idling. The needs of improvement in term of engine efficiency at part load operation become more popular among the engine manufacturers. One of the main reasons for efficiency dropped at part load conditions is the flow restrictions at the throttle valve opening area due to nearly-close position to control amount of inducted air into the cylinder, which leads to increasing in pumping losses. Hence, there are a lot of studies and investigations have been carried out to tackle these problems without sacrificing the original performance. This paper will investigate further the engine efficiency, performance as well as fuel economy by using one-dimensional (1-D) simulation tool. A baseline simulation model of a 1.6 liters four cylinders, port fuel injection engine has been developed based on the actual engine geometries. This baseline model applied predictive combustion to predict the amount of cylinder pressure based on actual ignition and injection timing on bench. The simulated results show a very good agreement with the measured data. Additionally, this study also proved that the deactivation half of the cylinders can significantly reduce the pumping losses of fired cylinder while eliminated the pumping work of unfired cylinders.

Experimental and Numerical Analysis on the Influence of Direct Fuel Injection Into O2-Depleted Environment of a GDI-HCCI Engine

2020 ◽  
Author(s):  
Ratnak Sok ◽  
Jin Kusaka
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Injection Pressure ◽  
Single Pulse ◽  
Gasoline Direct Injection ◽  
Injection Timing ◽  
Rich Mixture ◽  
Intake Stroke ◽  
Shift Reaction ◽  
Direct Fuel Injection

Abstract Injected gasoline into the O2-depleted environment in the recompression stroke can be converted into light hydrocarbons due to thermal cracking, partial oxidation, and water-gas shift reaction. These reformate species influence the combustion phenomena of gasoline direct injection homogeneous charge compression ignition (GDI-HCCI) engines. In this work, a production-based single-cylinder research engine was boosted to reach IMEPn = 0.55 MPa in which its indicated efficiency peaks at 40–41%. Experimentally, the main combustion phases are advanced under single-pulse direct fuel injection into the negative valve overlap (NVO) compared with that of the intake stroke. NVO peak in-cylinder pressures are lower than that of motoring, which emphasizes that endothermic reaction occurs during the interval. Low O2 concentration could play a role in this evaporative charge cooling effect. This phenomenon limits the oxidation reaction, and the thermal effect is not pronounced. For understanding the recompression reaction phenomena, 0D simulation with three different chemical reaction mechanisms is studied to clarify that influences of direct injection timing in NVO on combustion advancements are kinetically limited by reforming. The 0D results show the same increasing tendencies of classical reformed species of rich-mixture such as C3H6, C2H4, CH4, CO, and H2 as functions of injection timings. By combining these reformed species into the main fuel-air mixture, predicted ignition delays are shortened. The effects of the reformed species on the main combustion are confirmed by 3D-CFD calculation, and the results show that OH radical generation is advanced under NVO fuel injection compared with that of intake stroke conditions thus earlier heat release and cylinder pressure are noticeable. Also, parametric studies on injection pressure and double-pulse injections on engine combustion are performed experimentally.

Effect of Fuel Injection Timing Relative to Ignition Timing on the Natural-Gas Direct-Injection Combustion

2001 ◽  
Author(s):  
Zuohua Huang ◽  
Seiichi Shiga ◽  
Takamasa Ueda ◽  
Nobuhisa Jingu ◽  
Hisao Nakamura ◽  
...  
Keyword(s):  
Heat Release ◽  
Late Stage ◽  
Equivalence Ratio ◽  
Fuel Injection ◽  
Direct Injection ◽  
Injection Timing ◽  
Ignition Timing ◽  
Fuel Injection Timing ◽  
Initial Stage ◽  
Wide Range

Abstract Effect of fuel injection timing relative to ignition timing on natural gas direct-injection combustion was studied by using a rapid compression machine. The ignition timing was fixed at 80 ms from the compression start. When the injection timing was relatively earlier (injection start at 60 ms), the heat release pattern showed slower burn in the initial stage and faster burn in the late stage, which is similar to that of flame propagation of a premixed gas. In contrast to this, when the injection timing was relatively later (injection start at 75 ms), the heat release rate showed faster burn in the initial stage and slower burn in the late stage, which is similar to that of diesel combustion. The shortest duration was realized at the injection end timing of 80 ms (the same timing as the ignition timing) over the wide range of equivalence ratio. The degree of charge stratification and the intensity of turbulence generated by the fuel jet is considered to cause these behaviors. Earlier injection leads to longer duration of the initial combustion, whereas the later injection does longer duration of the late combustion. Earlier injection showed relatively lower CO emission while later injection produces relatively lower NOx emission. It was suggested that earlier injection leads to lower mixture stratification combustion and later injection leads to higher mixture stratification combustion. Combustion efficiency maintained high value over the wide range of equivalence ratio.

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